And again, I remember that thou hast said that thou hast loved the world, even unto the laying down of thy life for the world, that thou mightest take it again to prepare a place for the children of men.
And now I know that this love which thou hast had for the children of men is charity; wherefore, except men shall have charity they cannot inherit that place which thou hast prepared in the mansions of thy Father.
The background to this scripture is Moroni pausing in his account of the people of Jared, and relating a conversation he had with the Lord. So "thou" in the scripture is the Lord. It is the Lord who laid down his life for the world. For us. He did so because He loves us. And this love is charity.
One would question how are we supposed to have this charity so that we can return to our Heavenly Father? Are we supposed to lay down our lives for others? Yes, but not in the way that our Savior did. We do so symbolically.
We give of ourselves when we serve in our church callings. We give of ourselves when we do home and visiting teaching. We give of ourselves when we share the Gospel. We give of ourselves when we parent our children. We give of ourselves when we try to be the best companion to our spouse that we can be. We give of ourselves when we pay our tithes and fast offerings. We give of ourselves when we listen to someone, give them a hug or a smile, or assist in whatever righteous way their soul and mind may need for peace and comfort.
Those are just a few ways in which we can give of ourselves. But whenever we give of ourselves, we are laying down our lives as the Savior would have us do. And then we are worthy to inherit our place in the kingdom of our Father.